*

Language, Cognition, and Evolution: Modularity versus Unity

by Peter Turney

When I first started reading about evolutionary psychology, I was excited by the insights into the human mind. The Adapted Mind gave me a new way of thinking about the mind. These insights were reinforced by my research on the Baldwin effect. As an AI researcher, I was eager to apply these new (to me) ideas to my own research. Arguably, the most relevant lesson of evolutionary psychology for the AI researcher is the modularity of mind. I began thinking of the mind in terms of modules (vertical, domain-specific modules, as opposed to horizontal, general-purpose modules), and I thought about how I could implement some of these modules in software. However, after a few years of trying to push this idea forward, with little success, I began to doubt the modularity of the mind. I now believe that the mind has much more unity than most evolutionary psychologists suppose.

The mind is neither entirely modular nor entirely unified; there is a continuum of possibilities. Some of the people on the modular end of the spectrum are Noam Chomsky, Steven Pinker, Jerry Fodor, Leda Cosmides, and John Tooby. On the unified end of the spectrum are the proponents of cognitive linguistics, such as George Lakoff and Gilles Fauconnier, and some neurologists and psychologists, such as Terrence Deacon and William Uttal. Much of the debate between these two ends of the spectrum is concerned with the modularity of language. Is language quite different from other forms of cognition; is there a module in the brain that is devoted to language? Or are language and cognition very closely connected, as the cognitive linguists argue?

My own beliefs now lie much more toward the unified end of the spectrum. It seems to me that the cognitive linguists, in books such as Women, Fire, and Dangerous Things and The Way We Think, are giving us much deeper insights into language and cognition than the evolutionary psychologists. Chapter 5 of Pinker’s latest book, The Stuff of Thought, examines Lakoff and Johnson’s thesis that metaphorical language is based on metaphorical cognition. At the beginning of the chapter, Pinker seems quite critical of Lakoff and Johnson, but his tone becomes very conciliatory towards the end of the chapter. In fact, it seems to me that Pinker’s own research, as described in The Stuff of Thought, shows a deep connection between language and general cognition, which is not entirely consistent with Pinker’s strong support of evolutionary psychology.

This debate is related to the controversial Sapir-Whorf hypothesis, often expressed as “language determines thought”. Recent evidence in support of the Sapir-Whorf hypothesis undermines the view the language is modular.

I fully agree that evolution has shaped the brain. The question is whether it has shaped the brain more towards the modular end of the spectrum or more towards the unified end of the spectrum. In my own research, my interest has moved away from the Baldwin effect, which connects evolution and learning, towards analogy-making, which might be the general mechanism that underlies cognition and language.

Filed under: Computational Linguistics, Evolution, Philosophy of Mind | Tagged: evolutionary psychology, modularity